Imbalances of the essential trace elements magnesium (Mg) and zinc (Zn) have recently been reported to play a role in disorders of metabolic syndrome (MetS) and microalbuminuria. The present study was performed to investigate the distribution and reference of serum values Mg and Zn and the ratios of urinary Mg to creatinine (Mg/Cre), urinary Zn to creatinine (Zn/Cre), albumin to creatinine (ACR) in spot morning urine, as well as the estimated daily dietary consumption of Mg (D-Mg) and Zn (D-Zn) among 156 older community dwellers (96 males, 60 females) with a mean age of 65.1±6.7 y.o., ranging from 40 to 74 years. The relationships between Mg/Cre and ACR, Zn/Cre and ACR, Mg/Cre and D-Mg and Zn/Cre and D-Zn were also determined. Serum Zn and D-Zn showed normal distribution. Serum Mg, Mg/Cre, Zn/Cre and D-Mg showed positive skewed leptokurtic distribution. ACR showed logarithmic normal distribution. There were weak positive significant relationship between log-transformed ACR and Zn/Cre (r=0.203, p<0.05) and ultra-weak positive significant relationship between D-Mg and Mg/Cre (r=0.158, p<0.05). The results suggest that Zn can leak into urine at the early stage of microalbuminuria, associated with logarithmic ACR value. The homeostatic regulation of Mg/Cre was disturbed by the degree of early-stage microalbuminuria. Although there is a concomitant increase of urinary Mg excretion with D-Mg, the same was not observed for Zn excretion. These findings will update the urinary Mg and Zn information of older community dwellers of the National Health Insurance System through the Health Checkups and Healthcare Advice Focusing on Metabolic Syndrome (Tokutei Kenshin Hokenshido) program in Japan, and will contribute to further research into the relation between their disturbance and microalbuminuria associated with metabolic syndrome.

Several plant species, such as Brassicaceae plants have the ability to effectively accumulate selenium (Se) in salubrious chemical forms. Here we investigated the beneficial effects of selenium as a micronutrient in broccoli sprout with a particular focus on its defense system against oxidative stress. We first generated a Se-enriched type of broccoli sprout by cultivating the plant in seleniferous medium. The Se-enriched plants showed a tendency to growth stimulation and significantly accumulated selenite, selenocysteine, Se-methylselenocysteine, andγ-glutamyl Se-methylselenocysteine, which were not detected in the plants grown without Se. Se-enriched plants also contained larger amounts of glutathione compared with Se-untreated plants, but otherwise the two types of plants appear to be comparable with respect to antioxidative potential under normal growth conditions. By contrast, Se-enriched plants developed a clearer predominance over Se-untreated ones in the tolerance to oxidative stress when exposed to paraquat such that generation of malondialdehyde and superoxide radical, a molecular readout of oxidative damage, was attenuated and conversely dehydroascobate reductase and glutathione reductase were upregulated along with increase in glutathione content. In addition, production of Se-methylselenocysteine and γ-glutamyl Se-methylselenocysteine were found to be promoted in response to the paraquat treatment. Our present results indicate that a Se-dependent antioxidation network including glutathione and antioxidative enzymes drives the protective mechanism counteracting oxidative stress in broccoli sprout, in which the two seleno-amino acid derivatives may act as newly identified participants.

短報

Objective: The aim of this study is to establish a simple sample preparation method for analysis of fluoride in biological materials with headspace gas chromatography-mass spectrometer (HS GC-MS).Methods: Urine samples were introduced into headspace glass vials with hydrochloric acid, trimethylchlorosilane and acetaldehyde as the internal standard. Trimethylfluorosilane (TMFS), a derivatized fluoride, was analyzed with HS GC-MS.Results: The calibration curve of TMFS was linear in the investigated range from 0.01 to 15 µg/mL. TMFS showed a constant peak area at pH lower than 3.Conclusion: A simple sample preparation and selective analytical method was established for analysis of fluoride in human urine. This method can be carried out without extraction and reduces solvent consumption.